From 51018f76904258c3d96f0acac4ec9fe851debde2 Mon Sep 17 00:00:00 2001
From: Anton Zuev <ant-zuev@inbox.ru>
Date: Fri, 10 Mar 2023 15:38:33 +0300
Subject: [PATCH 1/2] Add a test tests/bugs/gh_6778_test.py from fbtest.

---
 tests/bugs/gh_6778_test.py | 133 +++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 tests/bugs/gh_6778_test.py

diff --git a/tests/bugs/gh_6778_test.py b/tests/bugs/gh_6778_test.py
new file mode 100644
index 00000000..501a3d2d
--- /dev/null
+++ b/tests/bugs/gh_6778_test.py
@@ -0,0 +1,133 @@
+#coding:utf-8
+
+"""
+ID:          issue-6778
+ISSUE:       6778
+TITLE:       Inconsistent cursor-driven deletion
+DESCRIPTION:
+    https://github.com/FirebirdSQL/firebird/issues/6778
+    
+    Confirmed bug on: WI-V4.0.0.2436.
+    Checked on: 4.0.0.2448 - works fine.
+    No errors must be during execution of this code.
+FBTEST:      bugs.gh_6778
+"""
+
+import pytest
+from firebird.qa import *
+
+db = db_factory()
+
+fb4_test_script = """
+    create table a1 (id int);
+    create table a2 (id int);
+
+    create index ia1 on a1 (id);
+    create index ia2 on a2 (id);
+
+    commit;
+
+    insert into a1 values (1);
+    insert into a2 values (1);
+    insert into a2 values (1);
+
+    commit;
+
+    set plan;
+
+    set term ^;
+    execute block
+    as
+    begin
+      for select a1.id from a1, a2 where a2.id = a1.id+0 as cursor c do
+        delete from a1 where current of c;
+    end^
+    set term ;^
+
+    -- PLAN JOIN (C A1 NATURAL, C A2 INDEX (IA2))
+    -- Statement failed, SQLSTATE = 22000
+    -- no current record for fetch operation
+    -- -At block line: 5, col: 5
+
+    rollback;
+
+    set term ^;
+    execute block
+    as
+    begin
+      for select a1.id from a1, a2 where a2.id+0 = a1.id as cursor c do
+        delete from a1 where current of c;
+    end^
+    set term ;^
+
+    -- PLAN JOIN (C A2 NATURAL, C A1 INDEX (IA1))
+
+    rollback;
+"""
+
+fb4_expected_stdout = """
+    PLAN JOIN (C A1 NATURAL, C A2 INDEX (IA2))
+    PLAN JOIN (C A2 NATURAL, C A1 INDEX (IA1))
+"""
+
+fb5_test_script = """
+    create table a1 (id int);
+    create table a2 (id int);
+
+    create index ia1 on a1 (id);
+    create index ia2 on a2 (id);
+
+    commit;
+
+    insert into a1 values (1);
+    insert into a2 values (1);
+    insert into a2 values (1);
+
+    commit;
+
+    set plan;
+
+    set term ^;
+    execute block
+    as
+    begin
+        for
+            select a1.id from a1, a2 where a2.id = a1.id
+            PLAN JOIN (A1 NATURAL, A2 INDEX (IA2))
+            as cursor c
+        do
+            delete from a1 where current of c;
+    end
+    ^
+    rollback
+    ^
+
+    execute block
+    as
+    begin
+        for
+            select a1.id from a1, a2 where a2.id = a1.id
+            PLAN JOIN (A2 NATURAL, A1 INDEX (IA1))
+            as cursor c
+        do
+            delete from a1 where current of c;
+    end
+    ^
+    set term ;^
+"""
+
+fb5_expected_stdout = """
+    -- line 4, column 9
+    PLAN JOIN (C A1 NATURAL, C A2 INDEX (IA2))
+    -- line 4, column 9
+    PLAN JOIN (C A2 NATURAL, C A1 INDEX (IA1))
+"""
+
+act = python_act('db', substitutions=[('-- line(:)? \d+, col(umn)?(:)? \d+', '-- line, column')])
+
+@pytest.mark.version('>=4.0')
+def test_1(act: Action):
+    test_script = fb5_test_script if act.is_version('>=5') else fb4_test_script
+    act.expected_stdout = fb5_expected_stdout if act.is_version('>=5') else fb4_expected_stdout
+    act.isql(switches=['-q'], input=test_script)
+    assert act.clean_stdout == act.clean_expected_stdout

From d5dccfd1f543fa3bca8aebe505966ea5d0dc3e8a Mon Sep 17 00:00:00 2001
From: Pavel Zotov <p519446@yandex.ru>
Date: Fri, 10 Mar 2023 19:34:45 +0300
Subject: [PATCH 2/2] Update gh_6778_test.py

Minor change: provide two backslashes for each regexp special character.
---
 tests/bugs/gh_6778_test.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/bugs/gh_6778_test.py b/tests/bugs/gh_6778_test.py
index 501a3d2d..1b623897 100644
--- a/tests/bugs/gh_6778_test.py
+++ b/tests/bugs/gh_6778_test.py
@@ -123,7 +123,7 @@ fb5_expected_stdout = """
     PLAN JOIN (C A2 NATURAL, C A1 INDEX (IA1))
 """
 
-act = python_act('db', substitutions=[('-- line(:)? \d+, col(umn)?(:)? \d+', '-- line, column')])
+act = python_act('db', substitutions=[('-- line(:)?\\s+\\d+,\\s+col(umn)?(:)?\\s+\\d+', '-- line, column')])
 
 @pytest.mark.version('>=4.0')
 def test_1(act: Action):